Somewhere, probably in front of a brightly lit screen with Weird Al playing in the background, a bunch of pencil-pushing scientists are writing long formulas on whiteboards, looking at the formulas thoughtfully, and then trying to use all that science to make you nearly invulnerable to firearms.
Current body armor is great against most rifle, submachine gun, and pistol fire, but it's far from perfect. It's heavy, adding as much as 40 pounds to troops' loads, and it cracks under repeated hits. Against high-velocity and high-caliber rounds, it will typically give way, allowing the rounds to pierce the target anyway.
And all of that's without taking into account that the armor, when working perfectly and when hit by rounds it's designed to stop, can't absorb all the impact. Most of it gets transferred to the target, just over a larger surface, sometimes resulting in broken bones or internal bleeding.
So it could definitely deal with some serious improvements. And that's where the Institute for Soldier Nanotechnologies at the Massachusetts Institute of Technology comes in. They have projects in the works that could give rise to futuristic body armor.
One of the most exciting is possibly the "Superelastic Granular Materials for Impact Absorption." Yup, it's a boring title. This is science. They name stuff with "descriptive" titles instead of entertaining ones. But, basically, this is looking at how to give troops high-tech, wearable beanbags.
The idea is that a bunch of grains of elastic material or crystals can be packed into the armor and, as the armor is hit, the energy is dissipated by these objects through friction and "intra-particle martensitic phase transformation."
That last phrase is about a fairly complicated scientific process, but it's the same process that metal goes through when it's tempered. At its most basic level, the microstructures of certain metals change when heated or placed under extreme stress. So, if a bullet hits a material that will go through the martensitic transformation, then that material will absorb energy as it changes, possibly saving the soldier who doesn't have to absorb that energy instead.